1. Field of the Invention
The present invention relates to a patterned servo-type magnetic recording media and a magnetic recording and reproducing apparatus having the magnetic recording media.
2. Description of the Related Art
In recent years, in order to adapt to further high-density recording, much attention has been paid to a discrete track recording media in which adjacent recording tracks are separated from one another by guard bands consisting of a groove or a nonmagnetic material to suppress magnetic interference between the adjacent tracks. In manufacturing such a discrete track media, if both magnetic and nonmagnetic patterns defining recording tracks and magnetic and nonmagnetic patterns corresponding to signals in servo zones are formed by imprinting with a stamper, it makes possible to reduce costs, because such a method can eliminate servo track writing.
A magnetic disk has been proposed which has data recording zones in which grooves are formed along recording tracks, to which data is recorded, that are formed of protrusions between the grooves, and servo zones in which protrusions and recesses corresponding to servo signals are formed and magnetized so as to have opposite polarities, wherein the area of the protrusions is larger than that of the recesses in the servo zones (Jpn. Pat. Appln. KOKAI Publication No. 1999-161944).
The above conventional magnetic disk has a longitudinal recording layer deposited on a substrate on which protrusions and recesses are formed. A formatting operation must be performed after film deposition in order to magnetize the protrusions and recesses in the servo zones so as to have the opposite polarities. Further, a perpendicular recording layer cannot be readily used in such a magnetic disk, because it is difficult to magnetize the protrusions and recesses so as to have the opposite polarities. In this case, such a high-cost process that the whole media is subjected to DC demagnetization and then is reformatted with a write head is required, which makes the process disadvantageous.
On the other hand, if both magnetic patterns defining recording tracks and magnetic patterns corresponding to servo signals are formed by imprinting, the presence or absence of the magnetic material can be utilized as a servo signal. For such a magnetic disk, even when a perpendicular magnetic recording layer is formed, formatting is completed simply by DC demagnetization involving applying external fields at once. This is advantageous for increasing density while reducing costs.
However, it has recently been found that the thermal stability of recorded magnetization may be degraded in such a discrete track-type magnetic disk.